Apparatuses and methods for performing compare operations using sensing circuitry

ABSTRACT

The present disclosure includes apparatuses and methods related to performing compare and/or report operations using sensing circuitry. An example method can include charging an input/output (IO) line of a memory array to a voltage. The method can include determining whether data stored in the memory array matches a compare value. The determination of whether data stored matches a compare value can include activating a number of access lines of the memory array. The determination can include sensing a number of memory cells coupled to the number of access lines. The determination can include sensing whether the voltage of the IO line changes in response to activation of selected decode lines corresponding to the number of memory cells.

PRIORITY INFORMATION

This application is a Continuation of U.S. application Ser. No.13/952,054, filed Jul. 26, 2013, the contents of which are incorporatedherein by reference.

TECHNICAL FIELD

The present disclosure relates generally to semiconductor memory andmethods, and more particularly, to apparatuses and methods related toperforming compare operations using sensing circuitry.

BACKGROUND

Memory devices are typically provided as internal, semiconductor,integrated circuits in computers or other electronic systems. There aremany different types of memory including volatile and non-volatilememory. Volatile memory can require power to maintain its data (e.g.,host data, error data, etc.) and includes random access memory (RAM),dynamic random access memory (DRAM), static random access memory (SRAM),synchronous dynamic random access memory (SDRAM), and thyristor randomaccess memory (TRAM), among others. Non-volatile memory can providepersistent data by retaining stored data when not powered and caninclude NAND flash memory, NOR flash memory, and resistance variablememory such as phase change random access memory (PCRAM), resistiverandom access memory (RRAM), and magnetoresistive random access memory(MRAM), such as spin torque transfer random access memory (STT RAM),among others.

Electronic systems often include a number of processing resources (e.g.,one or more processors), which may retrieve and execute instructions andstore the results of the executed instructions to a suitable location. Aprocessor can comprise a number of functional units such as arithmeticlogic unit (ALU) circuitry, floating point unit (FPU) circuitry, and/ora combinatorial logic block, for example, which can be used to executeinstructions by performing logical operations such as AND, OR, NOT,NAND, NOR, and XOR logical operations on data (e.g., one or moreoperands). For example, the functional unit circuitry (FUC) may be usedto perform arithmetic operations such as addition, subtraction,multiplication, and/or division on operands.

A number of components in an electronic system may be involved inproviding instructions to the FUC for execution. The instructions may begenerated, for instance, by a processing resource such as a controllerand/or host processor. Data (e.g., the operands on which theinstructions will be executed) may be stored in a memory array that isaccessible by the FUC. The instructions and/or data may be retrievedfrom the memory array and sequenced and/or buffered before the FUCbegins to execute instructions on the data. Furthermore, as differenttypes of operations may be executed in one or multiple clock cyclesthrough the FUC, intermediate results of the instructions and/or datamay also be sequenced and/or buffered.

Executing instructions (e.g, as part of program execution) can involveperforming operations such as compare operations and the results can beprovided (e.g., reported) to the processing resources as part of theexecutional flow of an algorithm, for example. Such compare and reportfunctionality can enable, for instance, “if-then-else” programmaticflow, which is often part of program execution.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an apparatus in the form of a computingsystem including a memory device in accordance with a number ofembodiments of the present disclosure.

FIG. 2 illustrates a schematic diagram of a portion of a memory arraycoupled to sensing circuitry in accordance with a number of embodimentsof the present disclosure.

FIG. 3 illustrates a schematic diagram of a portion of a memory arraycoupled to sensing circuitry in accordance with a number of embodimentsof the present disclosure.

FIG. 4 illustrates an example of a method for performing a compareoperation in accordance with a number of embodiments of the presentdisclosure.

DETAILED DESCRIPTION

The present disclosure includes apparatuses and methods related toperforming compare operations using sensing circuitry. An example methodcomprises charging (e.g., precharging) an input/output (IO) line (e.g.,a local IO line (LIO line)) of a memory array to a pvoltage (e.g., aprecharge voltage). The method can include determining whether datastored in the memory array matches a compare value by activating anumber of access lines of the memory array and sensing a number ofmemory cells coupled to the number of access lines. The method caninclude sensing whether the voltage (e.g., precharge voltage) of the LIOline changes in response to activation of selected decode lines (e.g.,column decode lines) corresponding to the number of memory cells. In thepresent disclosure, a “line” is meant to refer to an operable couplingbetween at least two nodes.

A number of embodiments of the present disclosure can provide benefitssuch as improved compare and report functionality in association withdetermining whether a match exists between a compare value (e.g., aparticular data value and/or set of data values) and a data value storedin a memory array. For instance, a number of embodiments can provide foridentifying whether particular data is stored in a number of memorycells without transferring data out of the memory array and sensingcircuitry via a bus (e.g., data bus, address bus, control bus), forinstance. The determination of whether data stored in the array matchesthe compare value can be reported, for instance, to control circuitry(e.g., to an on-die controller and/or to an external host). Thedetermination of whether data stored in the array matches the comparevalue can be reported into the memory array. Such compare and reportfunctionality can be associated with performing a number of logicaloperations (e.g., AND, NOT, NOR, NAND, XOR, etc.). However, embodimentsare not limited to these examples.

Also, circuitry such as FUC associated with various processingresource(s) may not conform to pitch rules associated with a memoryarray. For example, the cells of a memory array may have a 4F² or 6F²cell size, where “F” is a feature size corresponding to the cells. Thedevices (e.g., logic gates) associated with FUC of previous systems maynot be capable of being formed on pitch with the memory cells, which canaffect chip size and/or memory density, for example.

In the following detailed description of the present disclosure,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration how one or more embodimentsof the disclosure may be practiced. These embodiments are described insufficient detail to enable those of ordinary skill in the art topractice the embodiments of this disclosure, and it is to be understoodthat other embodiments may be utilized and that process, electrical,and/or structural changes may be made without departing from the scopeof the present disclosure. As used herein, the designators “N,” “P,”“R,” etc., particularly with respect to reference numerals in thedrawings, can indicate that a number of the particular features sodesignated can be included. As used herein, “a number of” a particularthing can refer to one or more of such things (e.g., a number of memoryarrays can refer to one or more memory arrays).

The figures herein follow a numbering convention in which the firstdigit or digits correspond to the drawing figure number and theremaining digits identify an element or component in the drawing.Similar elements or components between different figures may beidentified by the use of similar digits. For example, 130 may referenceelement “30” in FIG. 1, and a similar element may be referenced as 230in FIG. 2. As will be appreciated, elements shown in the variousembodiments herein can be added, exchanged, and/or eliminated so as toprovide a number of additional embodiments of the present disclosure. Inaddition, as will be appreciated, the proportion and the relative scaleof the elements provided in the figures are intended to illustratecertain embodiments of the present invention, and should not be taken ina limiting sense.

FIG. 1 is a block diagram of an apparatus in the form of a computingsystem 100 including a memory device 120 in accordance with a number ofembodiments of the present disclosure. As used herein, a memory device120, a memory array 130, and/or sensing circuitry 150 might also beseparately considered an “apparatus.”

System 100 includes a host 110 coupled to memory device 120, whichincludes a memory array 130. Host 110 can be a host system such as apersonal laptop computer, a desktop computer, a digital camera, a mobiletelephone, or a memory card reader, among various other types of hosts.Host 110 can include a system motherboard and/or backplane and caninclude a number of processing resources (e.g., one or more processors,microprocessors, or some other type of controlling circuitry). Thesystem 100 can include separate integrated circuits or both the host 110and the memory device 120 can be on the same integrated circuit. Thesystem 100 can be, for instance, a server system and/or a highperformance computing (HPC) system and/or a portion thereof. Althoughthe example shown in FIG. 1 illustrates a system having a Von Neumannarchitecture, embodiments of the present disclosure can be implementedin non-Von Neumann architectures (e.g., a Turing machine), which may notinclude one or more components (e.g., CPU, ALU, etc.) often associatedwith a Von Neumann architecture.

For clarity, the system 100 has been simplified to focus on featureswith particular relevance to the present disclosure. The memory array130 can be a DRAM array, SRAM array, STT RAM array, PCRAM array, TRAMarray, RRAM array, NAND flash array, and/or NOR flash array, forinstance. The array 130 can comprise memory cells arranged in rowscoupled by access lines (which may be referred to herein as row lines,word lines or select lines) and columns coupled by sense lines (whichmay be referred to herein as digit lines or data lines). Although asingle array 130 is shown in FIG. 1, embodiments are not so limited. Forinstance, memory device 120 may include a number of arrays 130 (e.g., anumber of banks of DRAM cells). An example DRAM array is described inassociation with FIGS. 2 and 3.

The memory device 120 includes address circuitry 142 to latch addresssignals provided over an I/O bus 156 (e.g., a data bus) through I/Ocircuitry 144. Address signals are received and decoded by a row decoder146 and a column decoder 152 to access the memory array 130. Data can beread from memory array 130 by sensing voltage and/or current changes onthe sense lines using sensing circuitry 150. The sensing circuitry 150can read and latch a page (e.g., row) of data from the memory array 130.The I/O circuitry 144 can be used for bi-directional data communicationwith host 110 over the I/O bus 156. The write circuitry 148 is used towrite data to the memory array 130.

Control circuitry 140 decodes signals provided by control bus 154 fromthe host 110. These signals can include chip enable signals, writeenable signals, and address latch signals that are used to controloperations performed on the memory array 130, including data read, datawrite, and data erase operations. In various embodiments, the controlcircuitry 140 is responsible for executing instructions from the host110. The control circuitry 140 can be a state machine, a sequencer, orsome other type of controller (e.g., an on-die controller).

An example of the sensing circuitry 150 is described further below inassociation with FIGS. 2 and 3. For instance, in a number ofembodiments, the sensing circuitry 150 can comprise a number of senseamplifiers (e.g., sense amplifiers 206-1, . . . , 206-P shown in FIG. 2or sense amplifier 306 shown in FIG. 3) and a number of computecomponents (e.g., compute component 331 shown in FIG. 3), which maycomprise an accumulator and can be used to perform compare and reportoperations (e.g., on data associated with complementary sense lines). Ina number of embodiments, the sensing circuitry (e.g., 150) can be usedto perform compare and report operations using data stored in array 130as inputs and store the results of the logical operations back to thearray 130 without transferring via a sense line address access (e.g.,without firing a column decode signal). As such, various computefunctions can be performed within array 130 using sensing circuitry 150rather than being performed by processing resources external to thesensing circuitry (e.g., by a processor associated with host 110 and/orother processing circuitry, such as ALU circuitry, located on device 120(e.g., on control circuitry 140 or elsewhere)). In various previousapproaches, data associated with an operand, for instance, would be readfrom memory via sensing circuitry and provided to external ALU circuitryvia local I/O lines. The external ALU circuitry would perform computefunctions using the operands and the result would be transferred back tothe array via the local I/O lines. In contrast, in a number ofembodiments of the present disclosure, sensing circuitry (e.g., 150) canbe configured to perform logical operations on data stored in memory(e.g., array 130) and store the result to the memory without enabling alocal I/O line coupled to the sensing circuitry.

FIG. 2 illustrates a schematic diagram of a portion of a memory arraycoupled to sensing circuitry in accordance with a number of embodimentsof the present disclosure. In this example, the memory array is a DRAMarray of memory cells (MCs) 260-1, . . . , 260-N. In a number ofembodiments, the memory cells are destructive read memory cells (e.g.,reading the data stored in the cell destroys the data such that the dataoriginally stored in the cell is refreshed after being read). The memorycells 260-1, . . . , 260-N of the array in FIG. 2 can be arranged in anumber of rows coupled by word line 204 and columns coupled by senselines (e.g., digit lines) 205-1, . . . , 205-M. For ease of reference,the sense lines 205-1, . . . , 205-M represent respective pairs ofcomplementary sense lines (e.g., 305-1 and 305-2 in FIG. 3). Althoughonly one row and two columns of memory cells are illustrated in FIG. 2,embodiments are not so limited. For instance, a particular array mayhave a number of columns of memory cells and/or sense lines (e.g.,4,096, 8,192, 16,384, etc.). As an example, a gate of a particularmemory cell transistor (e.g., 302 in FIG. 3) can be coupled to itscorresponding word line (204), a source/drain region can be coupled toits corresponding sense line (e.g., 205-1), and a second source/drainregion of a particular memory cell transistor can be coupled to itscorresponding capacitor (e.g., 303 in FIG. 3).

The array in FIG. 2 can be coupled to sensing circuitry in accordancewith a number of embodiments of the present disclosure. In this example,the sensing circuitry comprises sense amplifiers 206-1, . . . , 206-Pand secondary sense amplifier (SSA) 268. The sensing circuitry can besensing circuitry 150 shown in FIG. 1. The sense amplifiers 206-1 to206-P are coupled to the respective sense lines 205-1 to 205-M. Thesense amplifiers 206-1 to 206-P can be sense amplifiers such as senseamplifier 306 described below in association with FIG. 3. The senseamplifiers 206-1 to 206-P are coupled to input/output lines 266-1 (IO)and 266-2 (IO_) via transistors 218-1 and 218-2, respectively. Columndecode lines 264-1 (CD-1) to 264-R (CD-R) are coupled to the gates oftransistors 218-1 and 218-2 and can be selectively activated to transferdata sensed by respective sense amps 206-1 to 206-P to the SSA 268 viaIO lines 266-1 and 266-2

In operation, sense amps (e.g., 206-1 to 206-P) can sense a data value(e.g., a logic “1” or “0”) stored in a memory cell (e.g., 260-1 to260-N) by amplifying a differential signal (e.g., voltage or current) onthe complementary sense lines (e.g., 205-1 to 205-M) responsive toactivation of a selected row line (e.g., 204). As an example, the senseamps 206-1 to 206-P can drive one of the sense lines (e.g., D) of thepair of complementary sense lines 205-1 to a first value (e.g., to asupply voltage such as Vcc), and the other sense line (D_) of the pairof complementary sense lines 205-1 to a second value (e.g., to areference voltage such as a ground voltage). In this manner, the datavalue stored by the memory cell (e.g., 260-1) can be determined based onwhich of the sense lines of the complementary sense line pair is drivento Vcc, for instance. The voltages of the complementary sense line pairs205-1 to 205-M can then be selectively transferred to the IO lines 266-1and 266-2 via activation of the column decode lines 264-1 to 264-R. Inthis manner, the data sensed by the sense amps 206-1 to 206-P can betransferred to the SSA 268 via IO lines 266-1 and 266-2. Often, the SSA268 may only be capable of storing a data value from a single cell(e.g., one of cells 260-1 to 260-N) at a particular time. As such, if itis desired to transfer the data stored in cell 260-1 to the SSA 268,then column decode line 264-1 would be activated, and if it is desiredto transfer the data stored in cell 260-N to the SSA 268, then columndecode 264-R would be activated. If both lines 264-1 and 264-R wereactivated, the SSA 268 may not be able to determine the actual storeddata values stored in either of the cells.

However, in various instances, it can be useful to selectively activatemore than one of the column decode lines (e.g., 264-1 to 264-R). Forexample, selectively activating a number of column decode lines can bedone in association with performing a compare operation in accordancewith a number of embodiments described herein. For instance, in a numberof embodiments of the present disclosure, the data path portion shown inFIG. 2 can be operated to determine whether data stored in a memoryarray (e.g., array 130) matches a compare value, which may be providedby an on-die control circuit (e.g., control circuitry 140) and/or byexternal control circuitry (e.g., host 110) as part of an “if-then-else”programmatic flow, for example.

In a number of embodiments, control circuitry (e.g., 140 in FIG. 1) canbe configured to charge (.e.g., precharge) an IO line (e.g., 266-1) to avoltage (e.g., a precharge voltage). For example, the IO line 266-1 canbe precharged to a voltage (e.g., a supply voltage such as Vcc)corresponding to a logic “1.” The control circuitry can be configured toselectively activate row lines (e.g., a row line including memory cells260-1, . . . , 260-N) and column decode lines (e.g., CD-1, . . . ,CD-R). Sensing circuitry (e.g., 150 in FIG. 1) can be configured tosense a number of selected memory cells (e.g., 260-1, . . . , 260-N)coupled to an activated row line. The sensing circuitry can beconfigured to determine whether the precharge voltage of the IO line266-1 changes in response to selective activation of column decode linesCD-1 to CD-R.

In a number of embodiments, the control circuitry (e.g., 140 in FIG. 1)can, in conjunction with the sensing circuitry, can be used to perform acompare function (e.g., to determine if data stored in the memory arraymatches a compare value). As an example, the IO line 266-1 can beprecharged to a particular voltage. The particular voltage can be avoltage corresponding to a data value. For instance the prechargevoltage can be a supply voltage such as Vcc, which may correspond to alogic “1,” or a ground voltage, which may correspond to a logic “0.”

Activation of column decode line CD-1 turns on transistors 218-1 and218-2, which provides voltages corresponding to the data stored in senseamp 206-1 to IO lines 266-1 and 266-2. As such, the precharge voltage ofIO line 266-1 can change based on the particular data value stored insense amp 206-1 (which represents the data stored in a particular memorycell such as cell 260-1). For example, if the sense amplifier 206-1senses a logic 0 (e.g., a ground voltage) stored in cell 260-1, then theprecharge voltage (e.g., Vcc) on the IO line 266-1 will be pulled down(e.g., lowered) when CD-1 is activated, and the change in the prechargevoltage change can be detected by the SSA 268. As such, the detectedchange in the precharge voltage indicates that the sensed memory cell(e.g., 260-1) stores a data value (e.g., 0) different from the datavalue (e.g., 1) corresponding to the precharge voltage. Similarly, ifthe sense amplifier 206-1 senses a logic 1 (e.g., Vcc) stored in cell260-1, then the precharge voltage (e.g., Vcc) on the IO line 266-1 willnot be pulled down when CD-1 is activated, and no change in theprecharge voltage will be detected by the SSA 268. As such, no detectedchange in the precharge voltage indicates that the sensed memory cell(e.g., 260-1) stores the same data value (e.g., 1) as the data value(e.g., 1) corresponding to the precharge voltage.

The above described ability of the SSA 268 to determine whether theprecharge voltage changes can be used to perform compare functions todetermine whether a particular compare value matches data stored in amemory array, for instance. As an example, if an operation requiresknowledge of whether a number of cells coupled to a particular row linestores a particular compare value (e.g., 0), the particular row line canbe activated along with the sense lines corresponding the number ofmemory cells. If any of the cells store a 0, then the precharge voltageof the IO line (e.g., local IO line) will be changed (e.g., pulleddown). The result of the operation can be reported, for instance, to therequesting control circuitry (e.g., on-die controller, host, etc.). Theresult of the operation can be reported into the memory array forfurther calculations. The determined result may be used as part ofcontinued execution of a particular algorithm. For instance, executionmay include not only determining if any of the memory cells of the rowstore a data value (e.g., 0), but which cell(s) store the data value. Assuch, subsets of the column decode lines may be selectively activated tocompare the data values stored by their corresponding cells to thecompare value, which can be used in association with binary searching,for instance.

The compare values used in association with compare operations can berequested by control circuitry coupled to the sense circuitry (e.g.,on-die controller) and/or by a number of other sources such as anexternal host, for instance. Similarly, results of compare operationscan be reported to various control circuitry and/or used to performfurther operations (e.g., logic operations) as part of if-then-elseprogrammatic flow prior to being reported to control circuitry.

FIG. 3 illustrates a schematic diagram of a portion of a memory array330 coupled to sensing circuitry in accordance with a number ofembodiments of the present disclosure. In this example, the memory array330 is a DRAM array of 1T1C (one transistor one capacitor) memory cellseach comprised of an access device 302 (e.g., transistor) and a storageelement 303 (e.g., a capacitor). In a number of embodiments, the memorycells are destructive read memory cells (e.g., reading the data storedin the cell destroys the data such that the data originally stored inthe cell is refreshed after being read). The cells of array 330 arearranged in rows coupled by word lines 304-0 (Row0), 304-1 (Row1),304-2, (Row2) 304-3 (Row3), . . . , 304-N (RowN) and columns coupled bysense lines (e.g., digit lines) 305-1 (D) and 305-2 (D_). In thisexample, each column of cells is associated with a pair of complementarysense lines 305-1 (D) and 305-2 (D_). Although only a single column ofmemory cells is illustrated in FIG. 3, embodiments are not so limited.For instance, a particular array may have a number of columns of memorycells and/or sense lines (e.g., 4,096, 8,192, 16,384, etc.). A gate of aparticular memory cell transistor 302 is coupled to its correspondingword line 304-0, 304-1, 304-2, 304-3, . . . , 304-N, a firstsource/drain region is coupled to its corresponding sense line 305-1,and a second source/drain region of a particular memory cell transistoris coupled to its corresponding capacitor 303. Although not illustratedin FIG. 3, the sense line 305-2 may also be coupled to a column ofmemory cells.

The array 330 is coupled to sensing circuitry in accordance with anumber of embodiments of the present disclosure. In this example, thesensing circuitry comprises a sense amplifier 306 and a computecomponent 331. The sensing circuitry can be sensing circuitry 150 shownin FIG. 1. The sense amplifier 306 is coupled to the complementary senselines D, D_ corresponding to a particular column of memory cells. Thesense amp 306 can be operated to determine a state (e.g., logic datavalue) stored in a selected cell. Embodiments are not limited to theexample sense amplifier 306. For instance, sensing circuitry inaccordance with a number of embodiments described herein can includecurrent-mode sense amplifiers and/or single-ended sense amplifiers(e.g., sense amplifiers coupled to one sense line).

In a number of embodiments, a compute component (e.g., 331) can comprisea number of transistors formed on pitch with the transistors of thesense amp (e.g., 306) and/or the memory cells of the array (e.g., 330),which may conform to a particular feature size (e.g., 4F², 6F², etc.).As described further below, the compute component 331 can, inconjunction with the sense amp 306, operate to perform various compareand report operations using data from array 330 as input and store theresult back to the array 330 without transferring the data via a senseline address access (e.g., without firing a column decode signal suchthat data is transferred to circuitry external from the array andsensing circuitry via local I/O lines (e.g., 266-1 in FIG. 2).

In the example illustrated in FIG. 3, the circuitry corresponding tocompute component 331 comprises five transistors coupled to each of thesense lines D and D_; however, embodiments are not limited to thisexample. Transistors 307-1 and 307-2 have a first source/drain regioncoupled to sense lines D and D_, respectively, and a second source/drainregion coupled to a cross coupled latch (e.g., coupled to gates of apair of cross coupled transistors, such as cross coupled NMOStransistors 308-1 and 308-2 and cross coupled PMOS transistors 309-1 and309-2. As described further herein, the cross coupled latch comprisingtransistors 308-1,308-2, 309-1, and 309-2 can be referred to as asecondary latch (the cross coupled latch corresponding to sense amp 306can be referred to herein as a primary latch).

The transistors 307-1 and 307-2 can be referred to as pass transistors,which can be enabled via respective signals 311-1 (Passd) and 311-2(Passdb) in order to pass the voltages or currents on the respectivesense lines D and D_ to the inputs of the cross coupled latch comprisingtransistors 308-1, 308-2, 309-1, and 309-2 (e.g., the input of thesecondary latch). In this example, the second source/drain region oftransistor 307-1 is coupled to a first source/drain region oftransistors 308-1 and 309-1 as well as to the gates of transistors 308-2and 309-2. Similarly, the second source/drain region of transistor 307-2is coupled to a first source/drain region of transistors 308-2 and 309-2as well as to the gates of transistors 308-1 and 309-1.

A second source/drain region of transistor 308-1 and 308-2 is commonlycoupled to a negative control signal 312-1 (Accumb). A secondsource/drain region of transistors 309-1 and 309-2 is commonly coupledto a positive control signal 312-2 (Accum). The Accum signal 312-2 canbe a supply voltage (e.g., Vcc) and the Accumb signal can be a referencevoltage (e.g., ground). Enabling signals 312-1 and 312-2 activates thecross coupled latch comprising transistors 308-1, 308-2, 309-1, and309-2 corresponding to the secondary latch. The activated sense amp pairoperates to amplify a differential voltage between common node 317-1 andcommon node 317-2 such that node 317-1 is driven to one of the Accumsignal voltage and the Accumb signal voltage (e.g., to one of Vcc andground), and node 317-2 is driven to the other of the Accum signalvoltage and the Accumb signal voltage. As described further below, thesignals 312-1 and 312-2 are labeled “Accum” and “Accumb” because thesecondary latch can serve as an accumulator while being used to performa logical operation. In a number of embodiments, an accumulatorcomprises the cross coupled transistors 308-1, 308-2, 309-1, and 309-2forming the secondary latch as well as the pass transistors 307-1 and308-2. As described further herein, in a number of embodiments, acompute component comprising an accumulator coupled to a sense amplifiercan be configured to perform a logical operation that comprisesperforming an accumulate operation on a data value represented by asignal (e.g., voltage or current) on at least one of a pair ofcomplementary sense lines.

The compute component 331 also includes inverting transistors 314-1 and314-2 having a first source/drain region coupled to the respective digitlines D and D_. A second source/drain region of the transistors 314-1and 314-2 is coupled to a first source/drain region of transistors 316-1and 316-2, respectively. The gates of transistors 314-1 and 314-2 arecoupled to a signal 313 (InvD). The gate of transistor 316-1 is coupledto the common node 317-1 to which the gate of transistor 308-2, the gateof transistor 309-2, and the first source/drain region of transistor308-1 are also coupled. In a complementary fashion, the gate oftransistor 316-2 is coupled to the common node 317-2 to which the gateof transistor 308-1, the gate of transistor 309-1, and the firstsource/drain region of transistor 308-2 are also coupled. As such,enabling signal InvD serves to invert the data value stored in thesecondary latch and drives the inverted value onto sense lines 305-1 and305-2.

In a number of embodiments of the present disclosure, a compareoperation can include activating a row of memory cells (e.g., row line204) to determine if there is a match in the row line (e.g., at leastone memory cell stores a compare value). A compare operation can beexpanded to include comparing a 32-bit compare value to data stored inthe array. For example, compare values of a number of memory cells canbe aggregated in an accumulator (as described above) to determine ifthere is a collection of compare values that match a 32-bit comparevalue.

Embodiments of the present disclosure are not limited to the particularsensing circuitry configuration illustrated in FIGS. 2 and 3. Forinstance, different compute component circuitry can be used to performlogical operations in accordance with a number of embodiments describedherein.

FIG. 4 illustrates an example of a method for performing a compareoperation in accordance with a number of embodiments of the presentdisclosure. At block 470, the method includes precharging aninput/output (IO) line (e.g., 266-1 in FIG. 2) of a memory array (e.g.,330 in FIG. 3) to a precharge voltage. The IO line (e.g., a local IOline) can be precharged, for instance, to a voltage corresponding to aparticular data value, such as a supply voltage (e.g., Vcc correspondingto logic 1) or a reference voltage (e.g., a ground voltage correspondingto logic 0). A number of embodiments can include precharging a LIO_line(e.g., 266-2 in FIG. 2) of a memory array to a precharge voltage. Thevoltage to which the LIO_line is precharged can be an inverse of avoltage to which the LIO line is precharged.

At block 472, the method includes determining whether data stored in thememory array matches a compare value. The compare value can be a valueprovided by an external host (e.g., an external processor) and/or an ondie controller. The compare value can include a number of different datavalues that the control circuitry is attempting to determine whether arestored in at least one memory cell in a memory array. The compare valuecan be stored in a number of memory cells. For example, the data can bestored in one, two, three, etc., memory cells. A match can refer to adetermination that a compare value provided by the control circuitry isstored in at least one memory cell of the array. A determination thatthe compare value is not stored in at least one memory cell can indicatethat there is not a match.

The determination of whether data stored in the memory array matches acompare value can be determined, at block 474, by activating a number ofrow lines of the memory array. The number of row lines can beselectively activated based on a characteristic of the row lines. Thenumber of row lines can include particular row lines that arepredetermined by a controller (e.g., an external host, an on-diecontroller).

The determination of whether data stored in the memory array matches acompare value can be determined, at block 476, by sensing a number ofmemory cells coupled to the number of row lines. The voltage of thememory cells of the row lines of the memory array can be sensed by thesense amplifiers and column decode lines can be activated to provide thevoltage of the sense amplifiers (and corresponding memory cells) to theLIO line.

The determination of whether data stored in the memory array matches acompare value can be determined, at block 478, by sensing whether theprecharge voltage of the LIO line changes in response to activation ofselected column decode lines corresponding to the number of memorycells. For example, the LIO line can be precharged to a supply voltage(e.g., Vcc) corresponding to a logic 1. A memory cell in the memoryarray may store a data value (e.g., logic 0) corresponding to a comparevalue that a controller is trying to locate (e.g., match). When thememory cell is activated and the voltage of the cell is provided to theLIO line (e.g., via the corresponding sense amp), the voltage on the LIOline (e.g., precharge voltage) will drop if the data value stored by thecell matches the compare value (e.g., if the data value stored by thecell is a logic 0). The secondary sense amplifier can detect the drop involtage and determine that a match has occurred. The determination ofthe match can be reported to circuitry that provided the compare value(e.g., an on die controller, an external host, etc.) and/or to someother control circuitry for further use. If a match is determined,further operations can be performed to determine a particular location(e.g., cell or cells) within the array where the match occurs.Peripheral control logic can read a data path to determine the comparestate of the memory array. Locating the match can include a searchmethod (e.g., a binary search) to determine which memory cell in thememory array matched. The match can occur at a number of memory cells(e.g, no memory cell, one memory cell, or a plurality of memory cells).

Although specific embodiments have been illustrated and describedherein, those of ordinary skill in the art will appreciate that anarrangement calculated to achieve the same results can be substitutedfor the specific embodiments shown. This disclosure is intended to coveradaptations or variations of one or more embodiments of the presentdisclosure. It is to be understood that the above description has beenmade in an illustrative fashion, and not a restrictive one. Combinationof the above embodiments, and other embodiments not specificallydescribed herein will be apparent to those of skill in the art uponreviewing the above description. The scope of the one or moreembodiments of the present disclosure includes other applications inwhich the above structures and methods are used. Therefore, the scope ofone or more embodiments of the present disclosure should be determinedwith reference to the appended claims, along with the full range ofequivalents to which such claims are entitled.

In the foregoing Detailed Description, some features are groupedtogether in a single embodiment for the purpose of streamlining thedisclosure. This method of disclosure is not to be interpreted asreflecting an intention that the disclosed embodiments of the presentdisclosure have to use more features than are expressly recited in eachclaim. Rather, as the following claims reflect, inventive subject matterlies in less than all features of a single disclosed embodiment. Thus,the following claims are hereby incorporated into the DetailedDescription, with each claim standing on its own as a separateembodiment.

What is claimed:
 1. A method, comprising: charging an input/output (IO)line of a memory array to a voltage; activating an access line of thememory array and at least two selected decode lines of the array at thesame time; and determining whether at least one memory cell coupled tothe access line stores a compare value by sensing whether the voltage ofthe IO line changes in response to the activation of the at least twoselected decode lines.
 2. The method of claim 1, wherein charging an IOline includes precharging an IO line of the memory array to a prechargevoltage.
 3. The method of claim 1, wherein charging the IO line to thevoltage includes charging the IO line to a supply voltage.
 4. The methodof claim 3, wherein the supply voltage corresponds to a particular datavalue.
 5. The method of claim 1, wherein charging the IO line to avoltage includes charging the IO line to a ground voltage.
 6. The methodof claim 5, wherein the ground voltage corresponds to a particular datavalue.
 7. The method of claim 1, wherein activating selected decodelines comprises activating a subset of the decode lines of the array. 8.The method of claim 7, including determining the subset of decode linesbased on a set of criteria of the subset.
 9. An apparatus comprising: anarray of memory cells; a controller configured to cause: precharging ofan input/output (IO) line of the array to a precharge voltage; selectiveactivation of an access line of the array; and selective activation ofat least two decode lines of the array at the same time; and sensingcircuitry coupled to the array and configured to: sense a number ofselected memory cells coupled to the activated access line; anddetermine whether the precharge voltage of the IO line changes inresponse to the activation of the at least two decode lines.
 10. Theapparatus of claim 9, wherein the controller comprises an on diecontroller.
 11. The apparatus of claim 9, wherein the controllercomprises an external host.
 12. The apparatus of claim 9, wherein theprecharge voltage corresponds to a particular data value and adetermined change in the precharge voltage of the IO line indicates thata selected memory cell corresponding to an activated decode line of thedecode lines stores a data value other than the particular data value.13. The apparatus of claim 9, wherein the sensing circuitry comprises asecondary sense amp configured to detect whether the precharge voltageof the IO line changes.
 14. The apparatus of claim 9, wherein adetermined change in the precharge voltage of the IO line indicates datain a memory cell matches a compare value.
 15. The apparatus of claim 9,wherein the control circuitry is configured to report a determinedchange in the precharge voltage of the IO line to a host.
 16. Theapparatus of claim 9, wherein the sensing circuitry is configured toprovide an indication that a determined change in the precharge voltageof the IO line was detected.
 17. An apparatus comprising: an array ofmemory cells; control circuitry configured to cause: charging of aninput/output (IO) line of the memory array to a voltage; selectiveactivation of a plurality of access lines at the same time; andselective activation of at least two decode lines at the same time; andsensing circuitry coupled to the memory array and configured todetermine whether the charged voltage of the IO line changes in responseto activation of the at least two decode lines.
 18. The apparatus ofclaim 17, wherein: charging an IO line to a voltage includes prechargingan IO line of the memory array to a precharge voltage; and a determinedchange in the precharge voltage of the IO line indicates that at leastone memory cell of memory cells coupled to the access lines matches acompare value.
 19. The apparatus of claim 17, wherein the sensingcircuitry comprises a number of accumulators coupled to a respectivenumber of primary sense amplifiers.
 20. The apparatus of claim 17,wherein the sensing circuitry configured to determine whether thecharged voltage of the IO line changes comprises a secondary senseamplifier coupled to the IO line.